earth science

Humboldtine

Humboldtine is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Humboldtine rather than just read about it. In short: Humboldtine is a rarely occurring mineral from the mineral class of "organic compounds" with the chemical composition FeC2O4•2H2O and is therefore a water-containing iron(II) oxalate or the iron salt of oxalic acid. Humboldtine crystallizes in the monoclinic crystal system, but only rarely develops well-formed, tabular to prismatic crystals with a resin-like sheen on the surfaces.

Key takeaways

Humboldtine belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Humboldtine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Humboldtine from memory before moving on to harder problems.

Reference excerpt

Humboldtine is a rarely occurring mineral from the mineral class of "organic compounds" with the chemical composition FeC2O4•2H2O and is therefore a water-containing iron(II) oxalate or the iron salt of oxalic acid. Humboldtine crystallizes in the monoclinic crystal system, but only rarely develops well-formed, tabular to prismatic crystals with a resin-like sheen on the surfaces. It is mostly found in the form of botryoidal or fibrous to earthy aggregates and crusty coatings from dull yellow to brownish yellow or amber yellow in color. It can be transparent to opaque. It can form from hematite in oxalic acid. With a Mohs hardness of 1.5 to 2, humboldtine is one of the softest minerals and can be scratched with a fingernail.

Etymology and history Humboldtine was first discovered by August Breithaupt in a weathered brown coal deposit near the municipality of Korozluky in Okres Most in the Czech Republic and described in 1821 by Mariano Eduardo de Rivero y Ustáriz (1798–1857), who named the mineral after the German naturalist Alexander von Humboldt. The mineral was already known and characterized when the IMA was founded (1959). Accordingly, humboldtine is listed as an officially recognized mineral.

Occurrence The mineral is known to be found in 30 localities, including Germany, Brazil, the U.K. and Canada. In 2023, during the digitization of the archive of the Bavarian Environment Agency (LfU), a 75 year old letter from a coal mine owner written in 1949 was found. It mentioned that mineral was found in coal mine near the town of Schwandorf. Analysis of the mineral was done which confirmed the discovery. The discovery doubled the amount of Humboldtine known so far.

Crystal structure Humboldtine crystallizes monoclinically in the space group C2/c (space group no. 15) with the lattice parameters a = 12.011 Å; b = 5.557 Å; c = 9.920 Å and β = 128.53°, with four formula units per unit cell.

Uses It is an important synthetic intermediate and also a key building block for the preparation of various advanced materials.

References

Illustrations

Worked examples

Example 1 — a first encounter with Humboldtine

Start with the simplest possible case. Write down what Humboldtine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Humboldtine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Humboldtine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Humboldtine

In research: Humboldtine appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Humboldtine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Humboldtine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Iron(II) minerals, Minerals, Minerals described in 1821, so understanding it makes those chapters shorter.
In everyday life: Look for Humboldtine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Humboldtine” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Humboldtine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Humboldtine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Humboldtine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Humboldtine in simple terms?

Why does Humboldtine matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Humboldtine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Humboldtine.